High end Class D amps?


Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
bluorion

Showing 9 responses by mike_in_nc

Got to say, I've listened to a couple of them based on older Hypex modules, and I thought they sounded really good. I can't help but wonder if some of the negative sentiment is not entirely based on sound.
Amps based on the PuriFi modules have received glowing reviews. One example is the NAD M33. There also are some small shops assembling amps from PuriFi and other components. Nord and Apollon are two.

I'm pretty sure that 6Moons really liked the PuriFi demonstrator amp. I find it difficult to follow their reviews, between gobbledygook, constant reference to products I don't know, and tiny paragraphs of text sandwiched between huge ads.
The idea that Class D amps are overly load sensitive was true with early implementations. We are way beyond that now. Take a look at this page about the PuriFi modules. With a 2-ohm load, the THD+N stays below 0.01% up to full rated power.

And to those who say, "The only good ones are made by XXXX." Really?  You've heard EVERY Class D amplifier out there, and under a wide variety of circumstances?
@milpai - The Apollons haven't replaced my other amp yet; I'm still deciding. They and the Bryston 4B3 are really nice amps, so it's not simple. Their gains are different, and since I have subs in the system, it's not trivial to swap one in and the other out while keeping levels constant. Indeed, it's proven to be more fiddling and fussing than I'm up for. The experience gives me appreciation of what audio reviewers deal with.

That said, things I notice about the Apollon amps are
  • Extremely quiet and neutral
  • More detail, with none of the etch or glare that can accompany that; for example, I'm pinpointing instruments in ensembles better and hearing lyrics more clearly
  • The Apollons seem better control the treble, possibly because of less interaction with my electrostatic main speakers
  • Both the Bryston and the Apollons have great imaging and soundstaging; both have great bass
  • I have a tendency to listen louder with the Apollons. Why? Is that good or bad? I don't know!
So, it's proven more difficult than I expected to form a definite preference. Maybe that itself says something useful -- I hope so.


Got to say, the PuriFi class D amps I got from Apollon sound REALLY good. Clear and detailed without any edge.
@milpai - You’re welcome. The "cubed" Brystons run cool, and the Apollons run very cool. I haven’t noticed a huge difference, though the Apollons probably generate less waste heat.

My speakers are a pair of Janszen Valentina P8. Janszen rates them at 6 ohms nominal, 4 ohms minimum. I would imagine that, like other electrostats, they offer a highly capacitive load.

I think the comment that Class D can’t handle low impedance speakers is audiophile truthiness -- it doesn’t reflect today’s technology. Look at the specs of the PuriFi modules, which can put out 500 watts into 2 ohms with 0.0003% THD.
Then next you lot may as well just tell us to use this 6000watt!!!!! Class-D Behringer for just $600us.
I didn't say that; I didn't say that all amps are equal, nor that they sound the same, nor that they are of the same quality.

I did say that I fail to see any relevance to this "doubling" business that has become an audiophile touchstone. Those who claim it is important seem to resort to pseudo-technical handwaving. Maybe there is a reason, but I've never seen it laid out in valid technical terms.

And YOU didn't answer MY question: If an amp can put out 500 watts at 2 ohms, why is it important that it put out no more than 250 watts at 4 ohms?
@georgehifi -- It doesn’t matter. It puts out 500 watts into 2 ohms. That’s enough for most users. I consider "doubling" an irrelevant factor. Does the amp generate enough power for the intended use? If so, it’s a good choice (as far as power goes). If not, it’s not.
By the way, your statement is logically equivalent to saying that if an amp does put out 500 watts at 2 ohms, it is somehow lacking if it provides more than 250 watts at 4 ohms or 125 watts at 8 ohms. Why should that be a problem?
@jaytor - For sure. I wasn’t sure I read the spec right . . . the output impedance of the 1ET400A is specified as <65μΩ @ 1kHz.  Sixty-five millionths of an ohm. The output terminals will add more impedance to the circuit than the module itself!